busybox/networking/ether-wake.c
Denys Vlasenko 72089cf6b4 config: deindent all help texts
Those two spaces after tab have no effect, and always a nuisance when editing.

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2017-07-21 09:50:55 +02:00

295 lines
9.3 KiB
C

/* vi: set sw=4 ts=4: */
/*
* ether-wake.c - Send a magic packet to wake up sleeping machines.
*
* Licensed under GPLv2 or later, see file LICENSE in this source tree.
*
* Author: Donald Becker, http://www.scyld.com/"; http://www.scyld.com/wakeonlan.html
* Busybox port: Christian Volkmann <haveaniceday@online.de>
* Used version of ether-wake.c: v1.09 11/12/2003 Donald Becker, http://www.scyld.com/";
*/
/* full usage according Donald Becker
* usage: ether-wake [-i <ifname>] [-p aa:bb:cc:dd[:ee:ff]] 00:11:22:33:44:55\n"
*
* This program generates and transmits a Wake-On-LAN (WOL)\n"
* \"Magic Packet\", used for restarting machines that have been\n"
* soft-powered-down (ACPI D3-warm state).\n"
* It currently generates the standard AMD Magic Packet format, with\n"
* an optional password appended.\n"
*
* The single required parameter is the Ethernet MAC (station) address\n"
* of the machine to wake or a host ID with known NSS 'ethers' entry.\n"
* The MAC address may be found with the 'arp' program while the target\n"
* machine is awake.\n"
*
* Options:\n"
* -b Send wake-up packet to the broadcast address.\n"
* -D Increase the debug level.\n"
* -i ifname Use interface IFNAME instead of the default 'eth0'.\n"
* -p <pw> Append the four or six byte password PW to the packet.\n"
* A password is only required for a few adapter types.\n"
* The password may be specified in ethernet hex format\n"
* or dotted decimal (Internet address)\n"
* -p 00:22:44:66:88:aa\n"
* -p 192.168.1.1\n";
*
*
* This program generates and transmits a Wake-On-LAN (WOL) "Magic Packet",
* used for restarting machines that have been soft-powered-down
* (ACPI D3-warm state). It currently generates the standard AMD Magic Packet
* format, with an optional password appended.
*
* This software may be used and distributed according to the terms
* of the GNU Public License, incorporated herein by reference.
* Contact the author for use under other terms.
*
* This source file was originally part of the network tricks package, and
* is now distributed to support the Scyld Beowulf system.
* Copyright 1999-2003 Donald Becker and Scyld Computing Corporation.
*
* The author may be reached as becker@scyld, or C/O
* Scyld Computing Corporation
* 914 Bay Ridge Road, Suite 220
* Annapolis MD 21403
*
* Notes:
* On some systems dropping root capability allows the process to be
* dumped, traced or debugged.
* If someone traces this program, they get control of a raw socket.
* Linux handles this safely, but beware when porting this program.
*
* An alternative to needing 'root' is using a UDP broadcast socket, however
* doing so only works with adapters configured for unicast+broadcast Rx
* filter. That configuration consumes more power.
*/
//config:config ETHER_WAKE
//config: bool "ether-wake (6.6 kb)"
//config: default y
//config: select PLATFORM_LINUX
//config: help
//config: Send a magic packet to wake up sleeping machines.
//applet:IF_ETHER_WAKE(APPLET_ODDNAME(ether-wake, ether_wake, BB_DIR_USR_SBIN, BB_SUID_DROP, ether_wake))
//kbuild:lib-$(CONFIG_ETHER_WAKE) += ether-wake.o
//usage:#define ether_wake_trivial_usage
//usage: "[-b] [-i IFACE] [-p aa:bb:cc:dd[:ee:ff]/a.b.c.d] MAC"
//usage:#define ether_wake_full_usage "\n\n"
//usage: "Send a magic packet to wake up sleeping machines.\n"
//usage: "MAC must be a station address (00:11:22:33:44:55) or\n"
//usage: "a hostname with a known 'ethers' entry.\n"
//usage: "\n -b Broadcast the packet"
//usage: "\n -i IFACE Interface to use (default eth0)"
//usage: "\n -p PASSWORD Append four or six byte PASSWORD to the packet"
#include "libbb.h"
#include <netpacket/packet.h>
#include <netinet/ether.h>
#include <linux/if.h>
/* Note: PF_INET, SOCK_DGRAM, IPPROTO_UDP would allow SIOCGIFHWADDR to
* work as non-root, but we need SOCK_PACKET to specify the Ethernet
* destination address.
*/
#ifdef PF_PACKET
# define whereto_t sockaddr_ll
# define make_socket() xsocket(PF_PACKET, SOCK_RAW, 0)
#else
# define whereto_t sockaddr
# define make_socket() xsocket(AF_INET, SOCK_PACKET, SOCK_PACKET)
#endif
#ifdef DEBUG
# define bb_debug_msg(fmt, args...) fprintf(stderr, fmt, ## args)
void bb_debug_dump_packet(unsigned char *outpack, int pktsize)
{
int i;
printf("packet dump:\n");
for (i = 0; i < pktsize; ++i) {
printf("%2.2x ", outpack[i]);
if (i % 20 == 19) bb_putchar('\n');
}
printf("\n\n");
}
#else
# define bb_debug_msg(fmt, args...) ((void)0)
# define bb_debug_dump_packet(outpack, pktsize) ((void)0)
#endif
/* Convert the host ID string to a MAC address.
* The string may be a:
* Host name
* IP address string
* MAC address string
*/
static void get_dest_addr(const char *hostid, struct ether_addr *eaddr)
{
struct ether_addr *eap;
eap = ether_aton_r(hostid, eaddr);
if (eap) {
bb_debug_msg("The target station address is %s\n\n", ether_ntoa(eap));
#if !defined(__UCLIBC__) || UCLIBC_VERSION >= KERNEL_VERSION(0, 9, 30)
} else if (ether_hostton(hostid, eaddr) == 0) {
bb_debug_msg("Station address for hostname %s is %s\n\n", hostid, ether_ntoa(eaddr));
#endif
} else {
bb_show_usage();
}
}
#define PKT_HEADER_SIZE (20 + 16*6)
static int fill_pkt_header(unsigned char *pkt, struct ether_addr *eaddr, int broadcast)
{
int i;
unsigned char *station_addr = eaddr->ether_addr_octet;
memset(pkt, 0xff, 6);
if (!broadcast)
memcpy(pkt, station_addr, 6);
pkt += 6;
memcpy(pkt, station_addr, 6); /* 6 */
pkt += 6;
*pkt++ = 0x08; /* 12 */ /* Or 0x0806 for ARP, 0x8035 for RARP */
*pkt++ = 0x42; /* 13 */
memset(pkt, 0xff, 6); /* 14 */
for (i = 0; i < 16; ++i) {
pkt += 6;
memcpy(pkt, station_addr, 6); /* 20,26,32,... */
}
return PKT_HEADER_SIZE; /* length of packet */
}
static int get_wol_pw(const char *ethoptarg, unsigned char *wol_passwd)
{
unsigned passwd[6];
int byte_cnt, i;
/* handle MAC format */
byte_cnt = sscanf(ethoptarg, "%2x:%2x:%2x:%2x:%2x:%2x",
&passwd[0], &passwd[1], &passwd[2],
&passwd[3], &passwd[4], &passwd[5]);
/* handle IP format */
// FIXME: why < 4?? should it be < 6?
if (byte_cnt < 4)
byte_cnt = sscanf(ethoptarg, "%u.%u.%u.%u",
&passwd[0], &passwd[1], &passwd[2], &passwd[3]);
if (byte_cnt < 4) {
bb_error_msg("can't read Wake-On-LAN pass");
return 0;
}
// TODO: check invalid numbers >255??
for (i = 0; i < byte_cnt; ++i)
wol_passwd[i] = passwd[i];
bb_debug_msg("password: %2.2x %2.2x %2.2x %2.2x (%d)\n\n",
wol_passwd[0], wol_passwd[1], wol_passwd[2], wol_passwd[3],
byte_cnt);
return byte_cnt;
}
int ether_wake_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int ether_wake_main(int argc UNUSED_PARAM, char **argv)
{
const char *ifname = "eth0";
char *pass;
unsigned flags;
unsigned char wol_passwd[6];
int wol_passwd_sz = 0;
int s; /* Raw socket */
int pktsize;
unsigned char outpack[PKT_HEADER_SIZE + 6 /* max passwd size */ + 16 /* paranoia */];
struct ether_addr eaddr;
struct whereto_t whereto; /* who to wake up */
/* handle misc user options */
opt_complementary = "=1";
flags = getopt32(argv, "bi:p:", &ifname, &pass);
if (flags & 4) /* -p */
wol_passwd_sz = get_wol_pw(pass, wol_passwd);
flags &= 1; /* we further interested only in -b [bcast] flag */
/* create the raw socket */
s = make_socket();
/* now that we have a raw socket we can drop root */
/* xsetuid(getuid()); - but save on code size... */
/* look up the dest mac address */
get_dest_addr(argv[optind], &eaddr);
/* fill out the header of the packet */
pktsize = fill_pkt_header(outpack, &eaddr, flags /* & 1 OPT_BROADCAST */);
bb_debug_dump_packet(outpack, pktsize);
/* Fill in the source address, if possible. */
#ifdef __linux__
{
struct ifreq if_hwaddr;
strncpy_IFNAMSIZ(if_hwaddr.ifr_name, ifname);
ioctl_or_perror_and_die(s, SIOCGIFHWADDR, &if_hwaddr, "SIOCGIFHWADDR on %s failed", ifname);
memcpy(outpack+6, if_hwaddr.ifr_hwaddr.sa_data, 6);
# ifdef DEBUG
{
unsigned char *hwaddr = if_hwaddr.ifr_hwaddr.sa_data;
printf("The hardware address (SIOCGIFHWADDR) of %s is type %d "
"%2.2x:%2.2x:%2.2x:%2.2x:%2.2x:%2.2x\n\n", ifname,
if_hwaddr.ifr_hwaddr.sa_family, hwaddr[0], hwaddr[1],
hwaddr[2], hwaddr[3], hwaddr[4], hwaddr[5]);
}
# endif
}
#endif /* __linux__ */
bb_debug_dump_packet(outpack, pktsize);
/* append the password if specified */
if (wol_passwd_sz > 0) {
memcpy(outpack+pktsize, wol_passwd, wol_passwd_sz);
pktsize += wol_passwd_sz;
}
bb_debug_dump_packet(outpack, pktsize);
/* This is necessary for broadcasts to work */
if (flags /* & 1 OPT_BROADCAST */) {
if (setsockopt_broadcast(s) != 0)
bb_perror_msg("SO_BROADCAST");
}
#if defined(PF_PACKET)
{
struct ifreq ifr;
strncpy_IFNAMSIZ(ifr.ifr_name, ifname);
xioctl(s, SIOCGIFINDEX, &ifr);
memset(&whereto, 0, sizeof(whereto));
whereto.sll_family = AF_PACKET;
whereto.sll_ifindex = ifr.ifr_ifindex;
/* The manual page incorrectly claims the address must be filled.
We do so because the code may change to match the docs. */
whereto.sll_halen = ETH_ALEN;
memcpy(whereto.sll_addr, outpack, ETH_ALEN);
}
#else
whereto.sa_family = 0;
strcpy(whereto.sa_data, ifname);
#endif
xsendto(s, outpack, pktsize, (struct sockaddr *)&whereto, sizeof(whereto));
if (ENABLE_FEATURE_CLEAN_UP)
close(s);
return EXIT_SUCCESS;
}